Quick RTL SDR Comparison

As part of a recent project, I’ve used a few different RTL SDR devices, and was surprised how drifty some of them are, one in particular. For their intended application – decoding wideband transmissions – this isn’t an issue, but if you want to use one to decode RTTY then it certainly is – the signal will soon drift outside of the audio passband unless the SDR is retuned.

My project is on a Raspberry Pi, where I found that all but one (see the test results below) was basically unusable. So I did some quick tests on my desk, with a Windows PC running Airspy, for a crude visual comparison of drift rates. I tested 4 devices:

NooElec Nano 2

A very old E4000-based SDR

Current model R820T2 SDR

NooElec Aluminium-cased SDR

1 – NooElec Nano2

Poorest of the bunch.

2 – E4000

Better.

3 – R820T2

Not better.

4 – Ali cased

Much, much better.

As such, the metal-cased NooElec is the only one I could recommend.

Of course, there are much better SDRs out there – the Funcubes, SDR Play and Airspy models, and for chasing or tracking balloons you should really spend the extra money – but for bench testing then this particular RTL SDR is just fine.